<!DOCTYPE html>
<style>td { width: 50px; height: 50px; padding: 0; background-color: yellow }</style>
<div style="overflow: hidden; width: 100px; height: 100px">
  <table style="margin-top: -30px; border-spacing: 0">
    <tr>
      <td rowspan="2" style="background-color: blue"></td>
      <td></td>
    </tr>
    <tr>
      <td></td>
    </tr>
  </table>
</div>
